Yeah, always been a slippery slope, Dio vs Vignette, and what constitutes it.

You could ask 10 different people and likely get 10 different answers.

I was once told that a Vignette "CAN'T" have any vehicles, because if it did, it would be a diorama.

At our club and show, we categorize a Diorama as "something that tells a story", and a Vignette, "a moment in time"

Good example, I am currently working on a Trumpeter E-100 Jagdpanzer, and I am going to put it on a simple Miniart base, one of their new ones called "Country Road" which is basically just a road with a partial wall on one side.

I plan on putting a commander figure in the commander's hatch....now if I just left it as is, commander riding high as the tank drives by....I would consider it a Vignette, as it is a "moment in time", however is say I added another figure say standing beside the tank, either handing something up to the commander, or just talking to the commander, then to me that would then be a Diorama, as it is now "telling a story" because the 2 figures are interacting together. You could still argue that it is still just a moment in time I suppose, but there is much more dynamic to the scene if the commander is talking to someone on the ground. Could be discussing the weather...if they have seen any allied forces, whatever you want the story to be.